Question: If $x \triangleright y = xy+4x-y$ and $x \oslash y = x^{2}-2y^{2}$, find $(5 \oslash 2) \triangleright -4$.
Explanation: First, find $5 \oslash 2$ $ 5 \oslash 2 = 5^{2}-2(2^{2})$ $ \hphantom{5 \oslash 2} = 17$ Now, find $17 \triangleright -4$ $ 17 \triangleright -4 = (17)(-4)+(4)(17)-(-4)$ $ \hphantom{17 \triangleright -4} = 4$.